Process of making aluminum chloride



Patented Feb. 3, 1925.

UNITED STATES PATENT OFFICE.

CHARLES E. PARSONS, OF NEW YORK, Y., AND SAMUEL PEACOCK. OF WHEELING,

WEST VIRGINIA, ASSIGNORS TO METAL RESEARCH CORPORATION, OF NEW YORK. 1

N. Y., A CORPORATION OF DELAWARE' PROCESS OF MAKING ALUMINUM CHLORIDE.

No Drawing.

To all whom it may concern:

Be it known that we, CHARLES E. PARSONS and SAMUEL PEAoooK, citizens of the United States, residing at, respectively, New York and l heeling, in the counties of New York and Ohio, and States of New York and Vest Virginia, have invented certain new and useful Improvements in Processes of Making Aluminum Chloride; and we do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to a process of making aluminum chloride Al Cl and has for its object to improve the procedures heretofore proposed.

lVith these and other objects in view the invention consists inthe novel steps and combinations of steps constituting the process all as will be more fully hereinafter disclosed and particularly pointed out in the claims.

In carrying out this invention anhydrous aluminum chloride is produced by re-acting upon alumina with carbonyl chloride, COCl or by the action of said carbonyl chloride on slag, an aluminum salt or a suitable mineral.

The temperature of a commercial react-ion Velocity is a minimum at about 400 C. and as anhydrous aluminum chloride Al Cl is volatile at 200 C., a separation is effected by the customary sublimation method.

Carbonyl chloride COCl on the other hand, is produced by the interaction of sodium chloride NaCl usually called com mon salt and carbon monoxide, CO. Any alkali metal or alkaline earth chloride is also effectual. salt When in contact with carbon and in the presence of carbon monoxide, CO, and in the absence of any oxidizing reagent, forms carbonyl chloride and sodium oxide. As a beginning and ending equation, the reaction may be stated thus 2NaCl+2CO:N-a O+COCl +C Carbonyl chloride COCl is completely At about 1400 C common.

Application filed March 29, 1924. Serial No. 702,963.

dissociated at 900 C. and moves up the shaft as carbon monoxide and'free chlorine. Upon cooling to 800 C. and less, the carbonyl chloride reforms in the presence of coke.

It is proposed, in this invention, to make carbonyl chloride in: a shaft furnace and under the customary operating restrictions of an iron producing blast furnace. Common salt melts at about 800 C. and sublimes freely at 1100 C. Common salt in vapor form, at about 1400 C. in contact with coke and carbon monoxide CO at the same temperature, will react to produce free chlorine and sodium oxide.

As an industrial operation, the common salt constantly present 1n the process must always be present in excess of the proportions indicated by the reaction. More or less will be vaporized as such; and, escaping contact with carbon, will rise inthe furnace to a point of condensing temperature: about 800 C., or 1475 F. The condensed common salt then moves down with the furnace charge, and is again vaporized; until, with a suitable number of such returns, the vapor space of the high temperature zone of the furnace becomes stable at such high partial pressure of the vapor of sodium chloride, that no more is vaporized as such, except to replace the salt converted to carbonyl chlo ride and free chlorine.

There is also another well known major reaction in the interaction of carbon and common salt, at high temperatures, in the presence of nitrogen. That is, in a blast furnace the gases of the high temperature zone contain neither oxygen nor carbon dioxide, and are rich in nitrogen. Common salt vapor in contact with white hot carbon and in the presence of nitrogen, at about 1400 C., reacts to form sodium cyanamid and chlorine, thus The sodium cyanamid is volatile at its temperature of formation, and rises with the reaction and combustion gases until cooled to about 700 C. when the free chlorine reacts with carbon monoxide which is always present in excess due to the combustion of carbon at the tuyeres, and carbonyl chloride COCI' is formed. The sodium clyainamid is destroyed by carbonyl chloride, t us Na,CN +COGl =2NaC1+CO+O+N carbon monoxide CO in a strongly reducing atmosphere. Carbonyl chloride COCl forms, and in contact with alumina at temperatures between 400 C. and 700 C. re-

acts as follows The aluminum "chloride Al Cl being volatile at 200 0., passes out of the furnace in the exit gases. The sodium of the common salt, in the presence of silica, ultimates as silicate of sodium and leaves the furnace as molten slag.

It is obvious that other chlorides may be substituted for common salt, notably calcium chloride CaCl In this case the reactions would be much the same as if common salt were employed, except that no reduction of calcium oxide would occur, and calcium silicate would ultimate as molten slag. The furnace atmosphere would contain no vaporized chloride, and the physics of the op-v eration would be somewhat simplified; but the end product of carbonyl chloride .would remain the same.

In practical operation, a furnace of the blast furnace type would be charged through a suitable bell. with coke, common salt and an alumina containing substance such as alumina, bauxite, clay, slag, etc. More or less iron oxide is likely to be present in crude minerals or slag's. As the chargesinks in the furnace and a suitable temperature is reached, the carbonyl chloride converts the alumina and ferric oxide Fe O present to volatile anhydrous chlorides such as Al Cl and F6201, which being volatile at 200 (1, pass out of the furnace at the gas exit and are suitably collected. The remaining components of. the furnace charge, excepting the coke, pass out of the furnace as a molten' slag, and may be employed in glass manufacture. To illustrate the effect with the employment of kaolin, the following equations show the trend of the operation:

( 1) Al,Si,O 30001 A1 01 300 SiO (Solid) (Gas) (Gas) (Gas) (Solid) 2 2Si0, 3Na O Na,Si O,

(Solid) (Solid) (Liquid) Consolidated the reactions begin and end as:

(3) Al Si,O,+6NaCl=Al,01,+Na Si,O,

(Solid) (Solid) (Gas) (Liquid) If a chloride reagent of high boiling point chloride is less costly and produces a slag I by-product of higher value, and therefore its use is referentiah It Wlll now be clear that bythe action of carbonyl chloride on aluminum, free or com bined as a silicate, one is enabled to make aluminum chloride Al CI in a furnace of the blast type. Said chloride being volatile at the temperature of its production, it passes out of the top of said furnace, but is collected along with the combustion gases, and is separated therefrom by any suitable and well known means. I

What is claimed is 1. The process of making anhydrous aluminum chloride in a blast furnace which consists in providin afurnace charge containing carbon, ana kali-metal chloride as well as combined aluminum and capable of producing in the furnace reactions carbonyl chloride; and causing said carbonyl chloride to react with said aluminum to form the desired aluminum chloride.

. 2. The process of making anhydrous aluminumchloride in a blast furnace which consists in providing a furnace charge containing carbon, alumlna and sodium chloride and capable of producing carbonyl chloride when ignited; and causing said carbonyl chloride to react with said alumina to form the desired aluminum chloride.

3. The process of making anhydrous alumi- I num chloride in a blast furnace which consists in providing a furnace charge containing carbon sodium chloride and aluminum in a combined state; raising a portion of said charge to a temperature of substantially In testimony whereof we aflix our sigma-- CHARLES E. PARSONS. SAMUEL PEACOCK.

tures. 

